Add HA dropdowns, off image, flip fixes and refresh effects

Home Assistant: remove the Clock switch (its entity is deleted on connect),
add an IP sensor and Mode / Off image dropdowns whose options follow the
saved bitmaps. Remove the built-in "Nintendo border" bitmap.

Off image: a bitmap (or blank) left on the dots when the display switches off.

Nano: pause after each flip pulse and repeat pulses for changed dots, both
stored in EEPROM (G/N commands). Refresh effects (E command): instant,
sparkle, wipe, rain, from the middle out, diagonal, spiral, flip all then
reveal, push and random, optionally only for small changes. Effects run in
steps from loop() so serial input keeps flowing.

Web UI: flip settings, refresh effect and test patterns under Settings; the
System tab shows why the ESP32 last restarted. Settings records from
versions 1 and 2 are migrated. Firmware 2.3.0.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

lib/BROSE9323/README.md

@@ -19,6 +19,13 @@ The flags are set per environment in `platformio.ini` through `build_flags`. Don
 
 - In direct mode (`setDirect(true)`) every pixel is flipped right away, without a call to
   `display()`.
+- `setGap(us)` adds a pause after each flip pulse, `setPulses(n)` pulses each changed
+  dot `n` times. Full redraws (`display(true)`, the first `display()` after boot) pulse
+  the dots that look unchanged only once.
+- `setEffect(effect, ms)`: how `display()` shows a frame (`RefreshEffect` in
+  `dot_sequence.h`). Anything but `EFFECT_INSTANT` runs in steps from `update()`, which
+  must be called often; `busy()` says whether an effect is running. `display(true)` is
+  always instant. On the ESP32 these calls become the `G`, `N` and `E` commands.
 - `print()` maps German umlauts (ÄäÖöÜüß) to the code page 437 glyphs used by the GFX
   font.
 - On an ATmega168 the old buffer is left out to save RAM. Every `display()` call then